This paper is part of a comprehensive research project whose aim is to study the phenomenology of the special state of mind induced by the psychoactive Amazonian potion ayahuasca. Here, I focus on those aspects of the ayahuasca experience that are related to basic features of the human Consciousness. The effects of the potion are discussed in terms of a conceptual framework characterizing Consciousness as a cognitive System defined by a set of parameters and the values that they take. In various theoretical contexts, these values have been assumed to be basic, paradigmatic properties of human Consciousness. The phenomenological data pertaining to ayahuasca indicate that the features at hand can be modified. Following earlier suggestions by William James and Aldous Huxley, I conclude that any general theory of Consciousness should be based not only on the study of so-called ordinary Consciousness, but also on that of non-ordinary states.